Autoimmune comorbid diseases associated with lichen planus: a nationwide case-control study.

Background: Lichen planus (LP) is a chronic inflammatory disorder with unknown aetiology. The association between LP and various autoimmune diseases has been reported, but nationwide study of the relationship of LP with associated diseases is quite limited.
Objective: Our study aims to clarify the association between LP and a variety of autoimmune diseases in Taiwanese.
Methods: Data were obtained from the National Health Insurance Research Database (NHIRD) of Taiwan from 1997 to 2011. In total, 12,427 patients with LP and 49,708 age- and gender-matched controls were enrolled.
Results: Among patients with LP, there were significant associations with systemic lupus erythematosus (SLE) (multivariate odds ratio [mOR]: 2.87; 95% CI: 1.97-4.17), Sjögren's syndrome (mOR: 3.75; 95% CI: 2.66-5.28), dermatomyositis (mOR: 6.34; 95% CI: 1.82-22.16), vitiligo (mOR: 2.09; 95% CI: 1.31-3.32) and alopecia areata (mOR: 2.82; 95% CI: 2.20-3.62). On gender-stratified analyses, SLE and alopecia areata were significantly associated with LP in both genders. The association with Sjögren's syndrome was significant only in female patients. The associations with dermatomyositis and vitiligo became insignificant in both genders.
Conclusion: Lichen planus is associated with various autoimmune diseases. Further study is required to elucidate the possible underlying mechanisms and roles of autoimmunity in the aetiology of LP.
(© 2014 European Academy of Dermatology and Venereology.)